Metagenomic Analysis of a Southern Maritime Antarctic Soil
Metagenomics has been revolutionary in microbiology through the assessment of various microbial communities in complex ecosystems , primarily in temperate soil and marine environments (1). Metagenomics has successfully constructed DNA libraries which can be utilized to isolate newly discovered enzymes and drugs that have the potential to be innovative as well as important. Metagenomics combines DNA , mRNA , and protein analyses of microbial communities in various environments to enlighten scientists about the composition, function, and interaction the microbial community has with the environment in which it symbiotically thrives. By determining the interactions and purpose that microbes have with and in their environments, scientists can gain a greater understanding and sense of knowledge of the ecosystems found in the world and even universe. Metagenomic Analysis of Antarctic Soil Overview In one particular metagenomic study, Scientist David A. Pearce and team analyzed the microbial community found in southern maritime Antarctic soil (2). Specifically, Pearce and team investigated the biodiversity and functional potential of a soil community at Mars Oasis on Alexander Island in Antarctica. Antarctic soils are of interest because they are, in comparison to soil found in temperate or even tropical environments, extremely low in nutrients. Antarctic soils also provide indications of the potential effects of environmental change because for example, the Antarctic Peninsula in warming three times faster than the global average (2). The Mars Oasis has unique soil chemistry in comparison to surrounding areas, and this was another determining factor as to why this location was chosen as a site of metagenomic analysis. The goal of this study was to increase understanding and knowledge of the microbial taxonomic diversity in the soil and to determine the distribution of functional genes found in the soil. Metagenomic Analysis of Antarctic Process and Results The team applied 454 pyrosequencing technology to a metagenomic library constructed from soil genomic DNA. Samples were taken from the lower terrace of the Mars Oasis. The lower terrace onsisted of till , fluvial , and lacustrine sediments as well as streams and ponds which formed during the spring and summer months. The soil was collected by inserting four sterile Vacutainers with their lids removed 5cm into the soil, and then the lids were replaced. The samples were then put in a re-sealable bag and then placed in an insulated box until returned to the UK at -20 degrees C. After suspension and purification of the samples, the samples were run on a 20V large-welled 1% low melting point agarose gel. The team concluded that the clone library provided low coverage of the morjor microbial groups present. These major microbial groups' DNA sequence in comparison to the library demonstrated that the microbes found in such a harshly cold environment mainly consisted of functional genes ( >77%). The functional genes are for structure , carbohydrate metabolism , and DNA/RNA processing and modification. This study suggests that the bacteria (commonly Proteobacteria ''and ''Actinobacteria) are extremely generic and limited. Genetically though, there seemed to be a greater amount of heterogeneity, and the team concluded it was most likely because of a high level of divergence within the restricted lineages of microbes that had successfully colonized the Antarctic. From the 454 pyrosequencing data, 261,840 sequences contained taxonomic information; the sequences were further entered against the SEED database, and 322 phyla hits were found from eukarya, archaea, bacteria, and viruses. During the study, a protein (DUF1446) of unknown function was found. The Future of Metagenomics Most of the research to date has focused on temperate and not very extreme environments. As technology and the desire for knowledge improves and increases, harsher and more extreme environments ranging from the human gut to the hydrothermal vents have been tackled to expand taxonomic diversity and known information. Bibliography (1) http://aem.asm.org/content/77/4/1153.abstract (2) http://www.frontiersin.org/Journal/10.3389/fmicb.2012.00403/full